1. Field of the Invention
The present invention relates to a technique for decomposing substances contained in gases.
2. Description of the Related Art
In order to purify a gas containing substances to be decomposed, such as pollutants, a technique is known in which a gas obtained by vacuum extraction of soil polluted with organic chlorine compounds is irradiated with light with a specific wavelength to cause photolysis, and the gas is thereby purified. For example, U.S. Pat. No. 6,238,628 discloses a photolytic process by irradiation with ultraviolet light at a wavelength of 185 nm or 254 nm in order to purify a gas containing organic solvents, such as trichloroethylene, 1,1,1-trichloroethane, tetrachloroethylene, cis-1,2-dichloroethylene, and chlorofluorocarbons.
A method is also widely used in which a gas containing pollutants is brought into contact with an adsorbent, such as activated carbon, and the pollutants are adsorbed in the adsorbent for separation, and a purified gas is thereby obtained.
The adsorbent which has adsorbed pollutants may be incinerated as it is. In some cases, the pollutants are desorbed from the adsorbent using steam or the like for recovery, and the resultant solution is discharged out of the system to complete the treatment, as disclosed in Japanese Patent Publication No. 8-15529 or Japanese Patent Laid-Open No. 5-131113.
Currently, there is a demand for a decomposition technique for decomposing a substance to be decomposed with high efficiency.